Electromagnetic relay



Sept. 1, 1964 T. R. WELCH ETAL ELECTROMAGNETIC RELAY 5 Sheets-Sheet 2 Filed Oct. 26, 1960 THO/v05 Ross Na s/4 INVENTOR5 ATTOQHEY Sept. 1, 1964 T. R. WELCH ETALV ELECTROMAGNETIC RELAY Filed Oct. 26, 1960 3 Sheets-Sheet 3 THOMl-VS Ross WELCH ERNEST H- Tq v1.01?

INVENTORS BUM ATTORN United States Patent 3,147,349 ELECTROMAGNETIC RELAY Thomas Ross Welch, Los Angeles, and Ernest H. Taylor,

North Hollywood, Calif., assignors to Control l )ynamics Corporation, Los Angeles, Calif., a corporation of California Filed Oct. 26, 1960, Ser. No. 65,139 3 Claims. (Cl. 200-87) This invention relates to an electro magnetic relay struc ture and processes for fabricating the same, and particularly to a very tiny relay in the dimensional field which has come to be known as micro-miniature.

It is an object of this invention to provide a relay structure capable of being mass produced with economy and which is designed to withstand shock and vibration without faulty operation and without damage.

It is another object of this invention to provide a miniature relay which may be made from a minimum of parts, thereby simplifying the fabricating process.

It is another object of this invention to provide a relay design which by its very nature may be assembled and fabricated easily and simply and with relatively unskilled labor.

It is another object of this invention to provide a relay structure wherein maximum eificiency and conversion of electrical energy into a magnetic field and hence into operating pull is achieved.

It is another object of this invention to provide a relay design which is readily susceptible to variations and adjustments without major modification.

In accordance with these and other objects which will become apparent hereinafter, preferred forms of the present invention will now be described with reference to the accompanying drawings, wherein:

FIG. 1 is a cross sectional view of a relay constructed in accordance with the present invention;

FIG. 2 is a cross section taken on line 22 in FIG. 1;

FIG. 3 is a perspective view of the relay with the cover on and shown somewhat larger than actual size;

FIG. 4 is an exploded perspective view of the principal relay parts;

FIG. 5 is a plan view looking down on the wall or header of the relay which carries the electrical contacts;

FIG. 6 is a cross section of another form of relay constructed in accordance with the present invention and taken on line 6-6 in FIG. 7;

FIG. 7 is a sectional view taken on line 77 in FIG. 6;

FIG. 8 is a sectional view taken on line 88 in FIG. 7;

and

FIG. 10 is a cross section taken on line 10-10 in FIG.'7.

Referring to the drawings, 16 designates a frame struck from a single piece of sheet metal such as brass, or an alloy thereof. The frame 16 comprises a central base portion 17 which has a pair of coil mounting tabs 18 and 19 upturnedat each end of the base portion 17. Also integrally formed with the base portion 17 are a pair of leg portions 21 and 22 downturned at each side of the base 17. Each leg portion, for example, the leg portion 21, includes a pair of legs 23 and 24 and a skirt 25 extending between the legs 23 and 24. At the upper extremity of the leg 21, where it joins the base 17, is a tab, which is bent from the end of the skirt 25, first at right angles, to

FIG. 9 is a cross section taken on line 9-9 in FIG. 7;

3,147,349 Patented Sept. 1, 1964 parallel the walls 18, as shown at 26, and again at right angles to parallel the leg 23, as shown at 27. The tab 27 constitutes an armature stop as will be explained hereinafter. At the opposite end of the skirt portion 25, a wider tab is bent from the skirt, first at right angles and paralleling the walls 18 and 19, as shown at 28, and again at right angles to parallel the legs 23 and 24, as shown at 29. Wide tabs 29 are duplicated at diagonal corners, as shown in FIG. 5, and small tabs 27 are also duplicated at the other diagonal corners. The Wide tabs 29 constitute mounting tabs to which the pole pieces of the relay are spot welded, as will be explained hereinafter.

The upturned tabs 18 and 19 are provided with aligned holes 31 and 32, and placed between the tabs 18 and 19 is a cylindrical relay coil 33 having an axial hole or bore 34 aligned with the holes 31 and 32.

A pair of angular pole pieces 36 and 37 are inserted into the coil 33 from opposite ends thereof. Each of the pole pieces 36 and 37 has a semi-cylindrical coil portion 38 and 39, respectively, the flat faces of which mate within the hole or bore 34 to form the core for the relay coil 33. Extending integrally at right angles from each semi-cylindrical core 38 for example, is a pole piece 41 having an iuturned extension 42. The pole portion is spot welded on the tab 29 to secure the pole piece in position to the frame. Securement of the pole pieces 36 and 37 by such spot Welding also serves to secure the coil 33 to the frame 16 between the tabs 18 and 19.

To the underside of the base 17 is pivotally mounted an armature 43. The armature is mounted on a pivot pin 44 having at its upper end a shoulder and an enlarged head. The enlarged head is inserted through a central hole in the base 17 and the upper portion thereof is peened as shown at 46 by a spinning operation, to secure the pin 44 firmly to and beneath the base 17. The armature 43 is pivotally mounted over the pivot pin 44 by a journal bore 47 and is secured thereto by a U-shaped securement snapped into a groove on the end of the pivot pin 44.

The armature 43, like the pole pieces 36 and 37, is made of paramagnetic material, so that when magnetic flux is induced in the pole pieces by the coil 33, the armature 43 is caused to pivot slightly and come into firm magnetic engagement with the pole pieces 42. In so doing the armature actuates electric contacts in a manner to be described hereinafter.

The armature 43 is preferably formed of two pieces, 51 and 52, welded together in overlapping relation. The pieces 51 and 52 are identical and stamped from the same die. They are formed with transverse ridges or bosses 53 and with smaller circular bosses 54 before being bonded together. The formation of the boss 53 leaves on the opposite side a small groove, and the grooves are placed face to face as shown in FIG. 2 before the pieces 51 and 52 are bonded together. There is thus formed a coarse guide hole extending transversely from edge to edge through the armature 43. This guide hole is used to guide unerringly and with utmost accuracy a small drill which forms the finished bore 47, by means of which the armature is mounted over the pivot pin 44. By this formation of a guide hole, it is possible to accurately drill the bore 47 edgewise through the armature 43, a most diflieult task were it not for the preformed guide.

The lower or free extremities of the legs 23 and 24 are ensmalled, as shown at 61, for example, in order to provide mounting tabs which engage in notches 64 formed in a terminal wall or header 66 to which the frame 16 is mounted. In fabrication, the frame is mounted on the header 56, with the tabs 61 mating in the notches 64, and with the shoulders 67 resting flush against the inner or upper surface of the header 66. The tab 61 is of length slightly less than the thickness of the header 66, thereby leaving a small external well at the edge of each notch 64 into which solder may gather for a firm bond when securing the frame 16 to the header 66.

Eight terminals 71, 72, 73, 74, 76, 77, 78 and 79 (FIG- pass through the header 66 and are insulated therefrom by insulating grommets 81. To the inner ends of terminals 71, 74, 76 and 79 are secured leaf like stationary contacts 82, which are bent at right angles as shown at 83 to parallel the two switch blades 84 and 86. The switch blades or arms 84 and 86 are curled around and bonded to the inner ends of the terminals 73 and 77 and bend back and forth by the resiliency of the metal of which they are made, to constitute the switch operation. As seen in FIG. 5, there are thus constituted two independent double throw switches each having two positions. In one position (de-energized), for example, the switch blade 84 makes circuit between the terminal 73 and the terminal 71, while in the other (energized) position the switch blade 84 makes contact between the terminal 73 and the terminal 76. In similar manner the switch blade 86 makes selective contact from terminal 77 to terminal 74 or 79.

The switch blades 84 and 86 are actuated simultaneously by the oscillation of the armature 43 through the intermediacy of a respective pair of depending operating rods 87 and 88, to the ends of which are secured nonconducting contact spheres 89. The inner ends of the remaining two terminals, 72 and 78, pass upwardly on opposite sides on the armature 43 and are electrically connected to depending lead wires 91 of the coil 33. These terminals are prevented from short circuiting to other parts of the relay by a pair of insulating sleeves 92 that extend from the insulating grommet 81 in the base 61, to and through the passage holes 93 in the base 17, through which the leads 72 and 78 extend to join the leads 91 at the upper surface of the base 17.

The armature 43 is biased in a given direction (counterclockwise in FIG. 2) by means of a somewhat conical shaped compression spring 96, the smaller, outer end of which rests in a dimple 97 formed in a bendable tab 98 lanced out of the skirt 25. The inner, larger end of the spring 96 mates over the boss 54 formed on the armature 43. The lancing of the tab 98 from the skirt 25 provides a means for adjusting the stress in the spring 96 and hence adjusting the return bias of the armature 43. This is aided by cutting away a slot 101 in the skirt 25 at the end of the tab 98 when the tab 98 is lanced out. The slot 101 provides access for the blade of a narrow screw driver, in order to lift the tab if desired. To increase the compression of the spring 96 the fabricator need merely depress the tab 98 slightly with the I point of the screw driver.

The final adjustment of the armature return spring 96 is quite critical. It has been found that when this adjustment is achieved by a set screw applied to either end of the spring 96, the advancing or retracting of the spring must, of course, be accompanied by a turning of the screw. This in turn alters the torsion on the spring 96, which results in a change in its compression. This torsion is not uniform, because, as a rule, the torsional frictional engagement between the set screw and the end of the spring is quite variable and the spring may or may not slip with respect to the screw. Furthermore, when using an adjusting screw, there is danger of its turning under vibration and thus altering the spring adjustment. By the tab structure 98 there is no torsional moment whatever placed on the spring during adjustment and surety of final adjustment is thus attained.

The magnetic pull of the armature toward and against the core or pole piece 37 may be readily regulated by I designing the size of the pole tab 47 and also the size of the upturned portion 102 formed transversely on the end of the armature 43. The area of these engaging faces is an important factor in determining the force on the armature resulting from the magnetic flux induced by the coil 33; by adjusting these areas the magnetic force on the armature may be regulated and the magnetic impedance matched to the internal magnetic impedance within the coil 33.

Maximum efficiency in converting the magnetic field generated by the coil 33 into armature actuating flux is attained by matching the internal magnetic impedance inside the coil 33 to the external magnetic impedance outside the coil, i.e. the pole pieces 41 and the armature 43. Such magnetic impedance matching is aided greatly by the structure of the pole member 37, wherein the mating faces of the semi-cylindrical core pieces 38 and 39 are substantially parallel to the direction of the flux and a long cross sectional area of mating faces is thus achieved. Thus, a low magnetic reluctance within the coil 33 itself is achieved with maximum conversion of electric energy in the coil 33 into physical force on the armature 43.

The entire assembly is covered by a can or casing 104, having only one open face, which face is closed by the terminal wall or header 66, to complete the assembly as shown in FIG. 3. A small bevel or groove 106 (shown exaggerated in FIG. 4) is formed around the outer edge of the header 66. When the can 104 is placed over the relay and the header 66, this groove 106 cooperates with the adjacent edge of the can 104 to form a channel into which bonding solder may flow to complete a physical securement and hermetic seal completely around the relay. At the same time, the solder also fills the four tiny wells formed in the notches 64 at the extreme ends of the leg tabs 61.

As the assembly is inserted into the cam 104 it is guided securely into proper position by means of two indentations107 formed in opposite end walls in the can 104, which rest against the upper corners of the pole pieces 41, guiding them into position and holding the assembly in firm predetermined relation within the can 104. Mounting studs 111 are secured to the end wall of the can 104.

One of the indentations 107 also forms an elegant means for evacuating the assembly once it is completely sealed, and, if desired, inserting an inert gas. This is done by simply forming a small hole in the can 104 at the bottom of the indentation 107, either by drilling, or punching at the same time that the indentation 107 is formed. After the evacuation process, the hole is sealed by a tiny drop of solder 108. Since the solder 108 resides completely within the indentation 107, there is no added projection from the smooth can 104. This can be very important in micro-miniature equipment, where relays such as this are inserted into minute spaces with virtually no clearance. v

The arrangement of parts described hereinbefore makes possible an assembly technique that virtually obviates the necessity for adjustments after fabrication. Such adjustments are often required in order to insure that, when the relay is actuated, the armature 43 comes firmly and,

flush against the pole faces 41 and 42. In accordance with the present invention this is absolutely assured by the following observation and technique.

It has been discovered, in accordance with the present invention, that when soldering the ends of the leg portions 21 and 22 to the header 66, just sufficient stress and strain may be applied to the frame 16 to bring about an excellent magnetic contact between the opposite faces ofthe armature 43 and their respective pole pieces 41 and 42. This is effected in production by temporarily clamping, by means of a jig, the armature faces 51, 52

tightly against their respective pole faces 41,-"42, before the legs of the frame are bonded into the notches 64 of the header 66. After the solder bonding has been effected between the frame 16 and the header 66, the assembly is removed from the jig thus unclamping the armature from the pole faces. Any small stresses and strains which may have been placed in the frame 16 by the clamping of the armature thereto are retained by the bonding of the legs to'the header- 66. Thus, when the armature is unclamped, it is ready to oscillate back and forth and always return with flush engagement to the pole faces 41,42. 7

By virtue of the structure thus described above, a relay of micro-miniature proportions having great structural strength against vibration and shock may be simply fabricated. The symmetrical, pivoted nature of the armature inherently counter balances accelerative or shock forces, which tend to cause faulty or spurious operation. By making the frame 16 from a single integral sheet of brass, not only is great strength obtained, but simplicity of assembly is also made possible.

The legs 23, 24 are given added strength against bending, by inwardly indented channels 112 which extend from the free ends of the legs up almost to the bend, where the legs join the base portions 17. Thus, the bending strength is continued throughout virtually the entire length of the leg, and particularly into the skirt area 25.

The relatively simple structure described hereinbefore makes it possible to easily assemble the parts while they are held in predetermined position in assembly jigs, thus assuring that uniformity of assembly is attained.

The relay described occupies, with its can or container, less than 0.128 cubic inch, and, as noted hereinbefore, provides, two simultaneously operated, electrically independent double throw switches.

In FIGS. 6-10 there is illustrated a second form of the present invention which is even smaller than the first form heretofore described. The drawings shown are about five times the actual size of the fabricated item. The basic structure of this relay is the same as the relay heretofore described, and only those points of difference will now be set forth.

This second form of relay has only one switch, i.e. is a single pole, double throw switch, as shown in FIG. 9.

The frame 16a is basically similar to the frame 16 of the first form hereinbefore described, and has four legs 23a which extend downward and are bonded to the terminal wall or header 66a. Five terminals 730, 72a, 78a, 71a, and 76a extend through the header 66a, the central portion of which is made of insulating material as shown at 81a. The terminals 72a and 78a extend upward through channels or recesses 93a indented into the frame 16a, and connects to the leads of the coil 33a.

In the form shown in FIG. 6, the armature 43a is biased upward (axially), and also pivotally, by a single spring 96a, which thus serves as a return spring and also as a resilient stop, keeping the armature 43a pressed upwardly to a predetermined position against the underside of the frame 16a. The inner end of the spring 96a encircles the pivot pin 44a in a groove 201 and is then hooked over the edge of the armature 43a to provide a turning moment about the pivot pin. The other end of the spring 96a is mounted to the frame at 202. Groove 201 is made sufliciently wide that the spring 96a may press upwardly (to the right in FIG. 6) against the armature 43a thus holding it in position axially and at the same time biasing it to a predetermined position against the stop tab 27a.

Like its larger counterpart previously described, the smaller relay shown in FIGS. 6-10 has the elegant advantages of strength and ease of assembly with extremely tiny, micro-miniature size. It provides a double pole, single throw switch in a volume of less than 0.0455 cubic inch, including the can or container.

While the instant invention has been shown and described herein in what is conceived to be the'most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention which is therefore not to be limited to the details disclosed herein but is to be aiforded the full scope of the claims.

What is claimed is:

1. In a relay, a framestructure comprising a floor portion, a pair of arms and a pair of legs projecting in respectively .opposite directions from each of the two opposite sides thereof, said pairs being angularly displaced about an axis normal to said floor;

said pair of legs constituting base-mounting and spacing legs;

a base-member having supporting engagement with said mounting legs;

contact means on said base-member;

a coil disposed in alignment with and disposed in a position between said pair of arms;

pole pieces projecting through said arms into the coil and having offset pole-face par-ts extending to a level beyond said floor toward said mounting legs;

an armature bearing carried on said floor at least on the side thereof toward said mounting legs;

an armature pivotally mounted on said bearing for cooperative movement relative to said pole-face parts; and

said pair of legs having four tab portions offset toward one another within the planes established by said legs and in quadrant relationship, said pole pieces being secured for support to two diagonally positioned tab portions, and the remainder two positioned to act as stop members limiting the pivotal movement of said armature.

2. In a relay, a frame structure comprising a floor portion, a pair of arms and a pair of legs projecting in respectively opposite directions from each of the two opposite sides thereof, said pairs being angularly displaced 90 about an axis normal to said floor;

said pair of legs constituting base-mounting and spacing legs;

a base-member having supporting engagement with said mounting legs;

contact means on said base-member;

a coil disposed in alignment with and disposed in a position between said pair of arms;

pole pieces projecting through said arms into the coil and having offset pole-face parts extending to a level beyond said floor toward said mounting legs;

an armature bearing carried on said floor at least on the side thereof toward said mounting legs;

an armature pivotally mounted on said bearing for cooperative movement relative to said pole-face parts; and

a cantilever beam carried by said frame and projecting to a position laterally of said armature, a resilient compression member mounted between said beam and said armature, said resilient compression member contacting said armature on one side of the pivot established by said bearing and thereby providing a bias pressure upon said armature, the bias pressure being adjustable by bending said cantilever beam toward or away from said armature.

3. In a relay, a frame structure comprising a floor portion, a pair of arms and a pair of legs projecting in respectively opposite directions from each of the two opposite sides thereof, said pairs being angularly displaced 90 about an axis normal to said floor;

said pair of legs constituting base-mounting and spacing legs;

a base-member having supporting engagement with said mounting legs;

a coil disposed in alignment with and disposed in a position between said pair of arms;

pole pieces projecting through said arms into the coil References Cited in the file of this patent UNITED STATES PATENTS Charbonneau Oct. 18, 1955 Smith Dec. 15, 1959 Keeran Feb. 2, 1960 Distin July 26, 1960 Millunzi Oct. 25, 1960 Fisher et a1 Nov. 15, 1960 Smith Nov. 29, 1960 Brunicardi Oct. 17, 1961 Keller et a1. July 3, 1962 Jordan July 3, 1962 

1. IN A RELAY, A FRAME STRUCTURE COMPRISING A FLOOR PORTION, A PAIR OF ARMS AND A PAIR OF LEGS PROJECTING IN RESPECTIVELY OPPOSITE DIRECTIONS FROM EACH OF THE TWO OPPOSITE SIDES THEREOF, SAID PAIRS BEING ANGULARLY DISPLACED 90* ABOUT AN AXIS NORMAL TO SAID FLOOR; SAID PAIR OF LEGS CONSTITUTING BASE-MOUNTING AND SPACING LEGS; A BASE-MEMBER HAVING SUPPORTING ENGAGEMENT WITH SAID MOUNTING LEGS; CONTACT MEANS ON SAID BASE-MEMBER; A COIL DISPOSED IN ALIGNMENT WITH AND DISPOSED IN A POSITION BETWEEN SAID PAIR OF ARMS; POLE PIECES PROJECTING THROUGH SAID ARMS INTO THE COIL AND HAVING OFFSET POLE-FACE PARTS EXTENDING TO A LEVEL BEYOND SAID FLOOR TOWARD SAID MOUNTING LEGS; AN ARMATURE BEARING CARRIED ON SAID FLOOR AT LEAST ON THE SIDE THEREOF TOWARD SAID MOUNTING LEGS; AN ARMATURE PIVOTALLY MOUNTED ON SAID BEARING FOR COOPERATIVE MOVEMENT RELATIVE TO SAID POLE-FACE PARTS; AND SAID PAIR OF LEGS HAVING FOUR TAB PORTIONS OFFSET TOWARD ONE ANOTHER WITHIN THE PLANES ESTABLISHED BY SAID LEGS AND IN QUADRANT RELATIONSHIP, SAID POLE PIECES BEING SECURED FOR SUPPORT TO TWO DIAGONALLY POSITIONED TAB PORTIONS, AND THE REMAINDER TWO POSITIONED TO ACT AS STOP MEMBERS LIMITING THE PIVOTAL MOVEMENT OF SAID ARMATURE. 